Windows Internet Name Service (WINS) maps NetBIOS names to IP addresses. WINS performs a service for NetBIOS comparable to what DNS performs for TCP/IP. WINS is Microsoft's implementation of the earlier standard NetBIOS Naming Service (NBNS) of the NetBIOS over TCP/IP (NetBT) protocol.
References:
http://compnetworking.about.com/cs/windowsnetworkin1/g/bldef_wins.htm
http://technet.microsoft.com/en-us/library/cc771750(WS.10).aspx